Athens — Rising sea levels are what some nations fear most about global warming. But in Europe, climate change is likely to mean a new flood of immigrants from Africa and other poorer countries, according to a new report.

That was one of the issues before the heads of state from the 27-member European Union as they gathered in Brussels Thursday and Friday to address climate change and, in particular, the security threats it raises.

Unchecked climate change could not only cause a flood of new environmental migrants to Europe, it could spark instability in energy-producing states and lead to the collapse of fragile states around the world, says the report by EU foreign-policy chief Javier Solana and Benita Ferrero-Waldner, the European commissioner for external relations. Climate change, the report says, is a "threat multiplier" which "intensifies existing trends, tensions, and instability."

European leaders say they have an important role to play in leading the world towards an agreement to reduce greenhouse-gas emissions – and that's on this meeting's agenda, too. But increasingly, EU leaders are also seeing the need to prepare for the impacts of climate change at home. Meeting those challenges, analysts say, may require greater coordination of foreign policies.

"There's really a new approach and perspective developing," says Dirk Messner, director of the German Advisory Council on Global Change. "Climate change has been addressed until very recently as an environmental problem.... But dangerous climate change, beyond 2 degrees or so, will result in a destabilization processes around the world."

In 2007, the Solana report notes, all but one of the emergencies for which the UN appealed for humanitarian aid had climate dimensions. And new trading routes are opening in the Arctic as the polar ice caps melt, shifting the balance of power in the region.

Little in the report is new. In fact, it echoes a widely cited 2007 study by 11 retired American admirals and generals issued by CNA Corporation, a Virginia think tank.

But the stark warning from such high-ranking EU officials is likely to invigorate the debate in Europe about the links between climate and security – as well as highlight the urgency of coming to some sort of global agreement on reducing greenhouse-gas emissions.

Europe, experts say, is not likely to experience climate-related instability within its own territory – the brunt of the impact of global warming is likely to fall on the world's poor. But on the Continent's borders are regions, such as North Africa and the Middle East, that are both political fragile and acutely vulnerable to climate change.

"Migration is the real biggie," says Jeffrey Mazo, an expert on climate and security at the International Institute for Strategic Studies in London. "What's causing the migration is food insecurity and water insecurity and general insecurity in developing nations that don't have the infrastructure to cope with climate change impacts."

For countries like Greece and Spain, which lie on the edges of Europe and are already grappling with major illegal immigration crises, the threat of millions of environmental migrants is a worrying prospect. Already, the Greek government is planning to use development aid to address climate change-related problems in countries that are courses of illegal immigration, in hopes of pre-empting the problem.

Another effort that might help create jobs and stem migration is French President Nicolas Sarkozy's Mediterranean Union plan. On Thursday evening, he was scheduled to present the program intended to forge closer ties between Europe and North Africa and Middle Eastern countries. It includes the creation of a Euro-Mediterranean free trade area by 2010.

Critics of Mr. Sarkozy's efforts say that since 1995 the EU has given out $30 billion in grants and loans to 10 countries stretching from Morocco to Turkey, but with little result in terms of boosting democracy or ending poverty, reports the Associated Press.

Others argue that European officials are still uncertain of the scale of the potential problems caused by climate change. One often-cited estimate predicts that there will be 200 million climate migrants by 2050. But others put the figure nearer 20 million.

"It's taken people years to accept that climate change is actually true. Now it's a fact of life," says Jemini Pandya, a spokesperson for the International Organization for Migration, a United Nations organization. "Migration and climate change are two of the more pressing issues of the day. But until recently, there's been virtually no link between the two in terms of study and research."

Indeed, there's increasingly consensus that a crisis is looming, and experts say that a Europe-wide immigration policy – taking into account the issue of environmental migration – will have to be developed. The new EU foreign-policy representative, who will be appointed next year, will have to put climate issues at the top of the agenda.

"It's not just the European Union coming together," says Dr. Mazo. "Climate change is as much an opportunity as it is a threat on the security front, for strengthening all sorts of regional and global institutions."

Linking climate change to security is key to the issue being taken more seriously by Europe's political leaders. Dr. Messner says that until recently, climate change was the domain of environment ministers, who generally had relatively little power. Now, it's the realm of presidents and prime ministers.

"A wider community of the political class is seeing climate change as a serious issue," says Messner, who cites as an example the response of the German foreign minister to a recent report issued by his organization. "The political decisionmakers are now understanding what is going on."